The mechanism of reinforcement of nanocomposites polyurethane/graphene

2021 ◽  
pp. 237-240
Author(s):  
Gas.M. Magomedov ◽  
Gus.M. Magomedov ◽  
I.V. Dolbin
Keyword(s):  
Polymer Matrix ◽  
Modulus Of Elasticity ◽  
Interfacial Adhesion ◽  
Structure Type ◽  
Critical Content ◽  
Proposed Model ◽  
Main Factors ◽  
Nanofiller Content ◽  
Degree Of Reinforcement ◽  
Perfect Adhesion

The percolation model of reinforcement was used for the theoretical analysis of reinforcement mechanism for nanocomposites polyurethane/graphene. This model allows to elucidate influence of main factors (level of interfacial adhesion, nanofiller content, interfacial regions) on the degree of reinforcement or modulus of elasticity of the considered nanocomposites. It has been shown that for these nanocomposites actually nanofiller (graphene) serves as main reinforcing element. The sharp increasing of modulus of elasticity of nanocomposite occurs at achievement of critical content of nanofiller (∼9 % mas.). The same effect of increasing the level of interfacial adhesion is obtained by a polymer matrix-nanofiller, characterized by a transition from perfect adhesion to nanoadhesion. The structure type of nanofiller in polymer matrix (exfoliated or intercalated one) in one more factor. The proposed model is universal one for all nanocomposites polymer/2D-nanofiller.

scholarly journals The Size Effect of Strenthening for Dispersion-Filled Polymer Nanocomposites

2019 ◽  
pp. 23-28
Author(s):  
Patimat Rizvanova ◽  
Gasan Magomedov ◽  
Georgiy Kozlov
Keyword(s):  
Polymer Nanocomposites ◽  
Polymer Matrix ◽  
Interfacial Adhesion ◽  
Point Of View ◽  
Strong Increase ◽  
Filled Polymer ◽  
Large Size ◽  
Dispersed Filler ◽  
Level Of Aggregation ◽  
Main Factors

In the case of dispersion-filled polymer nanocomposites, it is assumed that a decrease in the size of dispersed nanoparticles leads to a strong increase in their degree of amplification. However, it is known that reducing the size of nanofiller particles intensifies the process of their aggregation, which ultimately dramatically increases the effective size of the nanofiller in the polymer matrix. Therefore, the question arises which nanofiller is more effective from a practical point of view – one having a small size of the initial particles, but highly aggregated, or another having a relatively large size of nanoparticles, but poorly aggregated. The aim of this work is to answer the above question. We have used two dispersion-filled polymer nanocomposites having the same polymer matrix, but filled with a dispersed filler, which size of the original particles differed by about 15 times. It is shown that the level of aggregation of dispersed nanofiller particles in the polymer matrix of the nanocomposite is controlled by two main factors: the size of its initial particles and the conditions for obtaining the nanomaterial, and the influence of the first factor prevails. The process of nanofiller aggregation significantly affects the level of interfacial adhesion and, as a consequence, the final properties of nanocomposites.

scholarly journals The structure of carbon nanotubes in a polymer matrix

2021 ◽  
Vol 23 (2) ◽  
pp. 223-228
Author(s):  
Georgii V. Kozlov ◽  
Gasan M. Magomedov ◽  
Gusein M. Magomedov ◽  
Igor V. Dolbin
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Polymer Matrix ◽  
Interfacial Layer ◽  
Glassy Matrix ◽  
Elastomeric Matrix ◽  
Strengthening Element ◽  
Form Ring ◽  
Nanofiller Content ◽  
Degree Of Reinforcement

We carried out an analytical structural analysis of interfacial effects and differences in the reinforcing ability of carbon nanotubes for polydicyclopentadiene/carbon nanotube nanocomposites with elastomeric and glassy matrices. In general, it showed that the reinforcing (strengthening) element of the structure of polymer nanocomposites is a combination of the nanofiller and interfacial regions. In the polymer matrix of the nanocomposite, carbon nanotubes form ring-like structures. Their radius depends heavily on the volume content of the nanofiller. Therefore, the structural reinforcing element of polymer/carbon nanotube nanocomposites can be considered as ring-like formations of carbon nanotubes coated with an interfacial layer. Their structure and properties differ from the characteristics of the bulk polymer matrix.According to this definition, the effective radius of the ring-like formations increases by the thickness of the interfacial layer. In turn, the level of interfacial adhesion between the polymer matrix and the nanofiller is uniquely determined by the radius of the specified carbon nanotube formations. For the considered nanocomposites, the elastomeric matrix has a higher degree of reinforcement compared to the glassy matrix, due to the thicker interfacial layer. It was shown that the ring-like nanotube formations could be successfully modelled as a structural analogue of macromolecular coils of branched polymers. This makes it possible to assess the effective (true) level of anisotropy of this nanofiller in the polymer matrixof the nanocomposite. When the nanofiller content is constant, this level, characterised by the aspect ratio of the nanotubes, uniquely determines the degree of reinforcement of the nanocomposites

scholarly journals Polymeric nanocomposites reinforced with nanowires: Opening doors to future applications

2018 ◽  
Vol 35 (1) ◽  
pp. 65-98 ◽  
Author(s):  
Ayesha Kausar
Keyword(s):  
Polymer Matrix ◽  
State Of The Art ◽  
High Strength ◽  
Processing Conditions ◽  
Polymeric Nanocomposites ◽  
Acrylic Polymers ◽  
Light Emitting ◽  
The Matrix ◽  
Nanofiller Content ◽  
Nanowire Structure

This article presents a state-of-the-art overview on indispensable aspects of polymer/nanowire nanocomposites. Nanowires created from polymers, silver, zinc, copper, nickel, and aluminum have been used as reinforcing agents in conducting polymers and non-conducting thermoplastic/thermoset matrices such as polypyrrole, polyaniline, polythiophene, polyurethane, acrylic polymers, polystyrene, epoxy and rubbers. This review presents the combined influence of polymer matrix and nanowires on the nanocomposite characteristics. This review shows how the nanowire, the nanofiller content, the matrix type and processing conditions affect the final nanocomposite properties. The ensuing multifunctional polymer/nanowire nanocomposites have high strength, conductivity, thermal stability, and other useful photovoltaic, piezo, and sensing properties. The remarkable nanocomposite characteristics have been ascribed to the ordered nanowire structure and the development of a strong interface between the matrix/nanofiller. This review also refers to cutting edge application areas of polymer/nanowire nanocomposites such as solar cells, light emitting diodes, supercapacitors, sensors, batteries, electromagnetic shielding materials, biomaterials, and other highly technical fields. Modifying nanowires and incorporating them in a suitable polymer matrix can be adopted as a powerful future tool to create useful technical applications.

Estimating the ‘In-Service’ Modulus of Elasticity and Length of Polyester Mooring Lines via a Non Linear Viscoelastic Model Governed by Fractional Derivatives

2012 ◽  
Author(s):  
Georgios I. Evangelatos ◽  
Pol D. Spanos
Keyword(s):  
Modulus Of Elasticity ◽  
Field Data ◽  
Fractional Derivatives ◽  
Viscoelastic Model ◽  
Mooring Lines ◽  
Static Modulus ◽  
Proposed Model ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

In this paper a non linear viscoelastic model governed by fractional derivatives is presented for modeling the in-service behavior of polyester mooring lines. In the formulation an iterative approach utilizing the Gauss-Newton minimization algorithm in conjunction with the catenary equations used to determine the static modulus of elasticity and the effective length of polyester mooring lines corresponding to calm sea conditions. Upon establishing the accuracy of the static modulus via comparison with field data, the catenary equations and the offshore platform’s position versus time are used to identify the polyester strain under developed-sea conditions. In this manner, time histories of stress and strain for polyester ropes in service conditions are obtained. Then, a non linear viscoelastic model involving fractional derivative terms is used to capture the in service polyester line behavior. For this, the tension of the proposed model corresponding to the actual polyester strain is compared at each time step to the tension obtained from the field data. Finally, the parameters of the proposed model are derived by minimizing the error in the least-squares sense over a large number of data points using the Levenberg-Marquardt algorithm. The numerically derived force-strain relationship is found to be in reasonable agreement with supplementary field and laboratory experimental data, the field data pertain to an offshore structure moored in position using polyester mooring lines operated in the Gulf of Mexico during Hurricane Katrina (August of 2005).

The Influence of Phases Division Surface in Nanocomposites Polymer/2D-Nanofiller on their Reinforcement Degree - The Percolation Model

2020 ◽  
Vol 869 ◽  
pp. 516-523
Author(s):  
Igor V. Dolbin ◽  
Gusein M. Magomedov ◽  
Georgii V. Kozlov
Keyword(s):  
Polymer Matrix ◽  
Composite Structure ◽  
Modulus Of Elasticity ◽  
Sample Volume ◽  
Percolation Model ◽  
Basic Factor ◽  
Critical Indices ◽  
Nanostructured Composites ◽  
Nanostructured Composite ◽  
Aggregation Level

The simple percolation model, in which critical indices are defined by the form of a reinforcing component of nanostructured composite structure, was proposed for the description of reinforcement degree for nanostructured composites polymer/2D-nanofiller. The indicated critical indices are close by absolute values to standard percolation indices. The form of reinforcing component controls the type of nanostructured composite. It has been shown that reinforcement degree of these nanomaterials is independent on modulus of elasticity of nanofiller, but is defined by its structure (aggregation level), created in polymer matrix. The percolation indices of a percolation model, which are due to the form of reinforcing component and nanocomposite type, are defined by its main characteristic – the fraction of phases division surface in overall sample volume and are the basic factor, controlling reinforcement degree of nanostructured composites.

scholarly journals Research on Improved Equivalent Diagonal Strut Model for Masonry-Infilled RC Frame with Flexible Connection

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Guang Yang ◽  
Erfeng Zhao ◽  
Xiaoya Li ◽  
Emad Norouzzadeh Tochaei ◽  
Kan Kan ◽  
...  
Keyword(s):  
Simulation Method ◽  
Structure Type ◽  
Frame Structure ◽  
Rc Frame ◽  
Infill Wall ◽  
Artificial Fish Swarm Algorithm ◽  
Rc Frame Structure ◽  
Proposed Model ◽  
Seismic Design Code ◽  
Artificial Fish Swarm

The reinforced concrete (RC) frame with masonry infill wall is one of the most common structural systems in many countries. It has been widely recognized that the infill wall has significant effects on the seismic performance of RC frame structure. During the Wenchuan earthquake (China 2008), a lot of infilled RC frame structures suffered serious damages due to the detrimental effects brought about by the infill wall rigidly connected to the surrounding frame. In order to solve this problem, flexible connection, introduced by Chinese designers, is recommended by the updated Chinese seismic design code, because of its effect to reduce the unfavorable interaction between infill wall and frame. Although infilled RC frame structure with flexible connection has a lot of advantages, but because of the lack of research, this structure type is seldom used in practical engineering. Therefore, it is of great significance to scientifically investigate and analyze the effects of flexible connection on structure behaviors of infilled RC frame. In this study, a macrofinite element numerical simulation method for infilled RC frame with flexible connection was investigated. Firstly, the effects of connection between infill wall and surrounding frame on in-plane behaviors of infilled RC frame were discussed. Secondly, based on deeply studying the equivalent diagonal strut models for infilled RC frame with rigid connection, an improved equivalent diagonal strut model for infilled RC frame with flexible connection was proposed. Employed with inversion analysis theory, the parameter in the proposed model was estimated through artificial fish swarm algorithm. Finally, applied with the existing experiment results, a case study was conducted to verify the effectiveness and feasibility of the proposed model.

THE MECHANISMS OF REINFORCEMENT OF NANOCOMPOSITES POLYURETHANE/CARBON NANOTUBE

2020 ◽  
pp. 3-7
Keyword(s):  
Carbon Nanotube ◽  
Polymer Nanocomposites ◽  
Modulus Of Elasticity ◽  
Maximum Degree ◽  
Micromechanical Model ◽  
Strong Interactions ◽  
High Modulus ◽  
Nanocomposite Structure ◽  
Practical Conclusion ◽  
Degree Of Reinforcement

The aim of present work is theoretical analysis of high values of reinforcement degree of nanocomposites polyurethane/carbon nanotube. For this two micromechanical models were used, showing identical results. The indicated models demonstrated, that densely-packed high-modulus interfacial regions, which serve the same reinforcing element of nanocomposite structure, as and nanofiller (carbon nanotubes) actually. The formation of interfacial regions defines by strong interactions polymer matrix – nanofiller. This means that nanofiller efficiency is controlled by its ability to generate densely-packed interfacial regions. It is important also to point out, that any micromechanical model, including mixtures rule, describes correctly modulus of elasticity of polymer nanocomposites, if in it real, but not nominal, characteristics of nanofiller were used. The content of interfacial regions in nanocomposite is controlled by structure of nanofiller. This allows to obtain important practical conclusion – for realization maximum degree of reinforcement it is necessary to cause structure of nanofiller, allowing to generate greatest content of interfacial regions. Absence of interfacial regions results to reduction of modulus of elasticity of nanocomposite in comparison with matrix polymer.

Tensile Properties and Morphology of Low Linear Density Polyethylene/Kapok Husk Eco-Composites

2015 ◽  
Vol 754-755 ◽  
pp. 161-165
Author(s):  
Nurul Fatin Syazwani binti Arshad ◽  
Salmah Husseinsyah ◽  
Lim Bee Ying
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Modulus Of Elasticity ◽  
Interfacial Adhesion ◽  
Linear Density ◽  
Filler Content ◽  
Rotor Speed ◽  
Elongation At Break ◽  
Morphology Study

This research focused on the utilization of kapok husk (KH) as filler in low linear density polyethylene (LLDPE). The effect of filler content on tensile properties and morphology of LLDPE/KH eco-composites were investigated. The eco-composites were prepared by using Brabender Plasticiser EC Plus at temperature 160 °C and rotor speed 50 rpm. The results indicated that the tensile strength and elongation at break decreased with KH content increased. However, the modulus of elasticity increased with increasing of KH content. The morphology study of eco-composites exhibit poor interfacial adhesion between KH and LLDPE.

scholarly journals Thermomechanical analysis of reinforced concrete columns exposed to fire

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Matheus Wanglon Ferreira ◽  
Luiz Carlos Pinto da Silva Filho ◽  
Mauro de Vasconcellos Real
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Three Dimensional ◽  
Concrete Columns ◽  
Thermomechanical Analysis ◽  
Structural Behavior ◽  
Mechanical Resistance ◽  
Reinforced Concrete Columns ◽  
Proposed Model ◽  
Main Factors

ABSTRACT: A three-dimensional (3D) transient numerical model for thermomechanical analysis developed with Finite Element Method (FEM) using the software ANSYS 19.1 is exposed in this paper. The proposed model aims to predict the structural behavior of reinforced concrete columns in a fire situation since it is known that high temperatures significantly reduce their mechanical resistance. For this, the main factors that govern their structural behavior should be considered. Analyses obtained by the proposed model were validated with results from experimental data, evidencing a good correlation between numerical and experimental fields.

scholarly journals Wireless Sensor Node Performance Analysis Under Mac Protocol IEEE 802.15.4

2020 ◽  
Vol 9 (3) ◽  
pp. 3790-3802
Keyword(s):  
Ieee 802.15.4 ◽  
Mac Protocol ◽  
Management Policy ◽  
Quality Of Services ◽  
Wireless Sensor Node ◽  
Resources Management ◽  
Proposed Model ◽  
Main Factors

The long-term use of sensors while guaranteeing good performance is a major challenge for sensor networks. To address this issue, it’s important to have a good resources management policy. So it is necessary to find the main factors which affected the behaviour of each sensors inside the networks to. In this paper we proposed an enhanced analytical model of CSMA/CA 802.15.4 standard and we study the performance of the proposed model under the MAC parameters and the density of network to find the keys parameters that impacted the quality of services (QoS) of the network.

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